Breakthrough method measures Universe's expansion rate and age with precision

The new technique measures the Universe's expansion rate, aiding age determination and enhancing understanding of the cosmos.
Kavita Verma
The Hubble Space Telescope captured this image of the galaxy cluster MACS J1149.5 +2233 and numerous Supernova Refsdal appearances with time-delay positions.jpg
The Hubble Space Telescope captured this image of the galaxy cluster MACS J1149.5 +2233 and numerous Supernova Refsdal appearances with time-delay positions

Patrick Kelly / NASA / ESA  

Professors Simon Birrer and Anja von der Linden from Stony Brook University have created a cutting-edge method to gauge the rate of the Universe's expansion. This method's data can be used to establish the age of the universe with precision and learn more about its intricate workings.

Utilizing Supernova Refsdal to measure expansion rate

The Hubble Space Telescope photograph of Supernova Refsdal, discovered by Patrick Kelly of the University of Minnesota in 2014, was used by the research team. Sjur Refsdal, an astronomer who developed a theory for calculating the Hubble constant in 1964, is honored by having his supernova bear his name. The first supernova in which this hypothesis was put into practice was supernova Refsdal.

Currently, studies of nearby supernovae and examination of cosmic microwave background (radiation) provide two precise assessments of the pace of our Universe's expansion. However, there remains disagreement among scientists on the composition and age of the Universe because these measurements are off by about 10%.

Using gravitational lensing to determine expansion rate

The study team came up with its estimate of the Universe's expansion rate by looking at four different photographs of the Supernova Refsdal outburst event in 2014. These numerous images were created due to a galaxy cluster's gravitational lensing effect, . The researchers were able to precisely quantify the Hubble constant thanks to the gaps in time between each image's appearance.

The work provides a measurement of the expansion rate that is compatible with those estimations, and its results are in line with those predicted by the cosmic microwave background. Additionally, this method might help settle long-standing disputes between scientists about estimates of the Universe's present pace of expansion.

The Legacy Survey of Space and Time (LSST), being carried out with the recently built Vera C. Rubin Observatory, is now being worked on by Professors Birrer and von der Linden. They want to measure the Hubble constant more precisely using systems found by the LSST.

The study, which is primarily supported by NASA through the National Science Foundation and the Space Telescope Science Institute, opens up new possibilities for precisely determining the age of the Universe and improving our understanding of its fundamental characteristics.

The journal Science published the team's findings.

Study Abstract: 

The gravitationally lensed Supernova Refsdal appeared in multiple images, produced through gravitational lensing by a massive foreground galaxy cluster. After the supernova appeared in 2014, lens models of the galaxy cluster predicted an additional image of the supernova would appear in 2015, which was subsequently observed. We use the time delays between the images to perform a blinded measurement of the expansion rate of the Universe, quantified by the Hubble constant (H0). Using eight cluster lens models, we infer H0=64.8+4.4−4.3 km s−1 Mpc−1, where Mpc is the megaparsec. Using the two models most consistent with the observations, we find H0=66.6+4.1−3.3 km s−1 Mpc−1. The observations are best reproduced by models that assign dark-matter halos to individual galaxies and the overall cluster.

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